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Biology is the study of living things. You meet it every day: the maize growing in a field, the goat you pass on the way to school, the mosquito that spreads malaria, and your own body breathing and growing. In these notes you learn what makes something alive, the difference between one-celled and many-celled organisms, and why biology matters to farmers, doctors and families in Zambia.
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25SCHOOLS FREE LEARNING NOTES FOR ZAMBIA FORM 1 · TERM 1 Introduction to Biology Biology Lesson notes for learners · Competence-Based Curriculum What biology is and its basic words Characteristics of living things Unicellular and multicellular organisms Branches of biology Importance of biology Check yourself INSIDE 1. 2. 3. 4. 5. 6. 25schools.com · Notes, quizzes and lesson plans for Zambian learners Biology is the study of living things. You meet it every day: the maize growing in a field, the goat you pass on the way to school, the mosquito that spreads malaria, and your own body breathing and growing. In these notes you learn what makes something alive, the difference between one-celled and many-celled organisms, and why biology matters to farmers, doctors and families in Zambia. AFTER THESE NOTES YOU SHOULD BE ABLE TO Explain what biology is and use basic biology words correctly Outline the seven characteristics of living things Tell the difference between unicellular and multicellular organisms and give examples Name the main branches of biology and say what each studies Explain why biology matters in agriculture, medicine and everyday life KEY WORDS Biology the scientific study of living things Organism any living thing, such as a plant, an animal, a mushroom or a bacterium Cell the smallest unit of life; all organisms are made of one or more cells Species a group of organisms of the same kind that can breed together Habitat the place where an organism finds food, water and shelter Unicellular made of only one cell Multicellular made of many cells Tissue a group of similar cells that do the same job together 1 What biology is and its basic words Biology is the scientific study of living things. A living thing is called an organism. A maize plant, a chicken, a mushroom, a fish in Lake Tanganyika and a person are all organisms. Things that are not alive, such as a stone, water or a bicycle, are non-living. Every organism is made of cells. A cell is the smallest unit of life. Some organisms are made of one cell and others of billions. Organisms of the same kind that can breed together form a species. All the chickens in a village belong to one species. Organisms live in a habitat, the place where they find food, water and shelter. A termite mound, a pond and a maize field are all habitats. • • • • • Form 1 Biology Lesson notes 25schools.com Page 2 of 7 Figure 1. Organisms are made of one cell or of many cells 2 Characteristics of living things All living things show seven characteristics. A non-living thing may seem to show one or two, but only living things show all seven. A useful way to remember them is the word MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition. Movement: living things change position or move parts of themselves. Animals move from place to place. Plants move too, but more slowly: a sunflower turns towards the sun and roots grow downwards. Respiration: all living cells release energy from food. This energy is used for movement, growth and keeping warm. Respiration is not the same as breathing. Breathing is bringing air in and out of the lungs. Respiration happens inside the cells. Sensitivity: living things detect changes in their surroundings, called stimuli, and respond to them. You pull your hand away from a hot pot. A mimosa plant, which grows wild in Zambia, folds its leaves when touched. Growth: living things increase in size and in the number of cells. A maize seedling becomes a tall plant. A calf becomes a cow. Reproduction: living things produce new organisms of their own kind. Hens lay eggs, maize makes seeds, and bacteria split in two. Reproduction keeps a species from dying out. Excretion: living things get rid of the waste made by their own chemical reactions. Animals excrete carbon dioxide through the lungs and urea in urine. Plants also excrete waste substances made in their cells. Excretion is different from egestion, which is removing undigested food as faeces. Faeces were never part of the body's chemical reactions, so egestion is not excretion. Nutrition: living things take in food to …
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